Japanese Patent Application Publication No. 2006-254629 discloses one example of an IPM rotating electric machine in which permanent magnets are embedded in a rotor core and in which electric energy is converted to mechanical energy by use of magnet torque and reluctance torque.
In such a conventional IPM rotating electric machine, a plurality of permanent magnets are arranged so that two corresponding permanent magnets define the letter V whose apex points toward the rotation axis of the rotor. The two corresponding permanent magnets form a single magnetic pole. The two corresponding permanent magnets have a same shape and are arranged symmetrically to each other with respect to a straight line radially extending through the apex of the letter V and the rotation axis. In other words, in a section view perpendicular to the rotation axis, the two corresponding permanent magnets are equal to each other in the length (width) parallel to the corresponding side of the letter V, the length (thickness) perpendicular to the corresponding side of the letter V and the angle with respect to the straight line.